In a method disclosed in German Patent 43 31 801 for manufacturing a twisted yarn in an integrated spinning and twisting process, two spinning devices are used for producing two spun yarns which spinning devices are in the form of an open end spinning rotor within a double twist device, which serves to twist the two spun yarns generated by the spinning devices according to the double twist principle. In this known method, respectively, the corresponding known device the loose fiber material is guided to the spinning devices through an envelope surface defined by the yarn balloon. Due to the integration of the spinning devices into the twisting device, the spinning devices in respect to their dimensions, especially their diameter, are subject to constructive limits. The known integrated spinning and twisting process is thus suitable only to a limited extent for processing worsted or combed yarns because worsted yarns, in general, have a fiber length of between 120 to 160 mm which requires spinning rotors with a correspondingly large diameter. In the know system it is also possible that complications occur with respect to guiding fibers of great staple fiber length through the yarn balloon.
From East German patent documents 78 710 a method for producing a twisted yarn according to the open end method is known; however, there is no disclosure in regard to what kind of method steps must be performed in order to twist the spun yarns produced in the open end spinning rotors.
It is therefore an object of the present invention to provide a combined spinning and twisting method which is especially suitable also for processing worsted yarn of great staple fiber length.